Jefferson Memorial Stone Deterioration and Root Cause Analysis

Background

• The stone exterior of the Jefferson Memorial in Washington, DC, was deteriorating.
• Repairing or painting over the worn areas was deemed too expensive.
• Park rangers turned to root cause analysis to find a solution.

Initial Observations

• High-powered sprayers were used to wash the memorial every two weeks.
• Frequent washings were needed due to bird droppings.

Root Cause Analysis (Five Whys)

1. Why was the stone deteriorating?
   • Due to frequent washings with high-powered sprayers.
2. Why were high-powered washings needed every two weeks?
   • Because of bird droppings on the memorial.
3. Why were there so many birds?
   • Birds were attracted to feed on spiders.
4. Why were there so many spiders?
   • Spiders were present because they fed on insects at night.
5. Why were there so many insects?
   • Insects were attracted by the lights shining on the memorial at night.

Solutions and Outcomes

• Initial Attempt:
  • Workers tried to use nets around the building to deter birds, but it was unsightly and ineffective as birds found ways around them.
• Effective Solution:
  • Reduced the time the memorial was illuminated at night to decrease insect attraction.
  • This led to a 90% reduction in insects.
  • With fewer insects, there were fewer spiders and consequently fewer birds.
• Unexpected Benefit:
  • Electricity cost savings due to reduced nighttime lighting.

Lessons Learned

• Root cause analysis can involve trial and error.
• The "Five Whys" method is not always limited to exactly five questions.
• Understanding and addressing the root cause can lead to effective, cost-saving solutions.

Additional Information

• For more details, refer to the further reading link provided in the original content.